The instant invention relates generally to a hydrogen infrastructure. More particularly, there is described herein the use of single stage metal hydride hydrogen compressors which also act as bulk hydrogen storage units for use in such a hydrogen infrastructure. These compressors are safe, efficient and reliable compressors having no moving parts to wear out. The compressors enable delivery of hydrogen for, by way of example and not limitation, refueling internal combustion engine or fuel cell vehicles.
Previously, in U.S. Pat. No. 6,305,442 B1 (the disclosure of which is incorporated herein by reference) a complete generation, storage, transportation, and delivery system for a hydrogen-based economy was described. This was made possible by hydrogen storage alloys that have surmounted the chemical, physical, electronic and catalytic barriers that have heretofore been considered insoluble. These alloys are fully described in U.S. Pat. No. 6,193,929 (""929) to Ovshinsky et al, the disclosure of which is incorporated herein by reference. This patent relates generally and specifically to alloys which solved the unanswered problem of having sufficient hydrogen storage capacity with exceptionally fast kinetics to permit the safe and efficient storage of hydrogen to provide fuel for a hydrogen based economy, such as powering internal combustion engine and fuel cell vehicles. A complete infrastructure system from xe2x80x9csource to wheelxe2x80x9d is the subject of U.S. Pat. No. 6,305,442 B1.
In the ""929 patent the inventors for the first time disclosed the production of Mg-based alloys having both hydrogen storage capacities higher than about 6 wt. % and extraordinary kinetics. This revolutionary breakthrough was made possible by considering the materials as a system and thereby utilizing chemical modifiers and the principles of disorder and local order, pioneered by Stanford R. Ovshinsky (one of the instant inventors), in such a way as to provide the necessary catalytic local order environments, such as surfaces and at the same time designing bulk characteristics for storage and high rate charge/discharge cycling. In other words, these principles allowed for tailoring of the material by controlling the particle and grain size, topology, surface states, catalytic activity, microstructure, and total interactive environments for storage capacity.
Hydrogen is the xe2x80x9cultimate fuelxe2x80x9d for the next millennium, and, it is inexhaustible. Hydrogen is the most plentiful element in the universe and can provide an inexhaustible, clean source of energy for our planet which can be produced by various processes which split water into hydrogen and oxygen. The hydrogen can be stored and transported in solid state form.
In the past considerable attention has been given to the use of hydrogen as a fuel or fuel supplement. While the world""s oil reserves are depletable, the supply of hydrogen remains virtually unlimited. Hydrogen can be produced from coal, natural gas and other hydrocarbons, or formed by the electrolysis of water, preferably via energy from the sun which is composed mainly of hydrogen and can, itself, be thought of as a giant hydrogen xe2x80x9cfurnacexe2x80x9d. Moreover hydrogen can be produced without the use of fossil fuels, such as by the electrolysis of water using nuclear or solar energy, or any other form of economical energy (e.g., wind, waves, geothermal, etc.). Furthermore, hydrogen, is an inherently low cost fuel. Hydrogen has the highest density of energy per unit weight of any chemical fuel and is essentially non-polluting since the main by-product of xe2x80x9cburningxe2x80x9d hydrogen is water. Thus, hydrogen can be a means of solving many of the world""s energy related problems, such as climate change, pollution, strategic dependancy on oil, etc., as well as providing a means of helping developing nations.
One of the major problems in utilizing hydrogen has been the need for a simple, efficient, reliable and cost effective means for compressing and simultaneously storing hydrogen. Metal hydride hydrogen compressors are known in the prior art. See, for example, U.S. Pat. Nos. 4,085,590; 4,402,187; 4,505,120; and 4,995,235. These hydrogen compressors all have common deficiencies, one of which is that they are energy inefficient. This is because they require multiple stages to compress the hydrogen from a low pressure to a higher (useful) pressure and each of these stages is not energy efficient. Each stage of the compression requires a heating and cooling cycle. This heating and cooling causes losses of up to one fifth of the useful energy (of combustion of the hydrogen) per cycle in waste heat. Thus, it would be useful to have a compressor which can compress the hydrogen from a low pressure to a high pressure in a single stage and thereby minimize the wasted heat.
In addition to the energy losses of multiple compression stages, these compressors do not achieve bulk storage of the hydrogen. Thus, the compressed hydrogen must be stored in gas tanks of other such storage units. This inability to provide for integrated compression and bulk storage exacerbates the heat loss problem, because each stage of the compressor must cycle very many times to provide useful quantities, while a combine storage and compression unit will only require one heating/cooling cycle to provide very large quantities of hydrogen.
Additionally, even if the prior art compressors tried to create bulk storage in their compressors, there remains the fact that the Mm-Ni type alloys have inherently low storage capacities (less than 1.5 wt. %) and cycling at temperatures higher than about 150xc2x0 C. causes the Mm alloys to form highly stable hydrides which will no longer cycle. Therefore these devices would be unreliable at the higher temperatures required for high pressures.
Thus, there remains a compelling and crucial a need in the art for a combined bulk storage and compression apparatus which is safe, efficient, reliable, cost effective and capable of storing and delivering large quantities of high pressure hydrogen. The combined bulk storage/single stage metal hydride hydrogen compressor of the instant invention overcomes the limitations of the prior art.
The objects of the instant invention include a combine bulk storage/single stage metal hydride compressor and a hydrogen storage alloy therefore. The instant invention also includes a hydrogen transportation/distribution infrastructure which incorporates the combine bulk storage/single stage metal hydride compressor. The combined bulk hydrogen storage/single stage metal hydride hydrogen compressor includes 1) a pressure containment vessel, which has at least one hydrogen inlet/outlet port for transferring hydrogen into and out of the vessel; 2) a hydrogen storage alloy disposed with the containment vessel, the hydrogen storage alloy being in sufficient quantity to provide for bulk storage of hydrogen and the hydrogen storage alloy having a plateau pressure of less than or equal to 500 psi at a temperature of less than or equal to 25xc2x0 C. and a plateau pressure greater than or equal to 1500 psi at a temperature of less than or equal to 200xc2x0 C.; and 3) a thermal management system for alternately heating and cooling the hydrogen storage alloy.
More preferable are alloys have a plateau pressure less than or equal to 400 psi at a temperature of less than or equal to 25xc2x0 C. and a plateau pressure greater than or equal to 2000 psi at a temperature of less than or equal to 200xc2x0 C. Even further preferred alloys have a plateau pressure less than or equal to 300 psi at a temperature of less than or equal to 25xc2x0 C. and a plateau pressure greater than or equal to 3600 psi at a temperature of less than or equal to 200xc2x0 C. Further preferred alloys have a plateau pressure less than or equal to 200 psi at a temperature of less than or equal to 25xc2x0 C. and a plateau pressure greater than or equal to 5000 psi at a temperature of less than or equal to 200xc2x0 C. The most preferred alloys have a plateau pressure of about 100 psi at a temperature of about 12xc2x0 C. and a plateau pressure of about 6000 psi at a temperature of about 180xc2x0 C.
Specifically the hydrogen storage alloy is an alloy is an AB2 alloy, such as a modified Tixe2x80x94Mn2 alloy comprising, in atomic percent 2-5% Zr, 26-32% Ti, 7-10% V, 8-20% Cr, 38-42% Mn; and at least one element selected from the group consisting of 1-6% Ni, 2-6% Fe and 0.1-2% Al. The alloy may further contain up to 1 atomic percent Misch metal. Examples of such alloys include in atomic percent: 1) 3.63% Zr, 29.8% Ti, 8.82% V, 9.85% Cr, 39.5% Mn, 2.0% Ni, 5.0% Fe, 1.0% Al, and 0.4% Misch metal; 2) 3.6% Zr, 29.0% Ti, 8.9% V, 10.1% Cr, 40.1% Mn, 2.0% Ni, 5.1% Fe, and 1.2% Al; 3) 3.6% Zr, 28.3% Ti, 8.8% V, 10.0% Cr, 40.7% Mn, 1.9% Ni, 5.1% Fe, and 1.6% Al; and 4) 4% Zr, 29.5% Ti, 8.5% V, 15.0% Cr, 38% Mn, 5% Ni.
The hydrogen transportation/distribution infrastructure system includes at least 1) a hydrogen purification/compression subsystem which purifies and compresses hydrogen; and 2) a hydrogen distribution subsystem which distributes hydrogen to end users, where one or both of these subsystems incorporates the combined bulk hydrogen storage/single stage metal hydride hydrogen compressor of the instant invention.
The hydrogen transportation/distribution infrastructure system may further include: a) a power generation subsystem; b) a hydrogen generation subsystem which uses power from said power generation subsystem to produce hydrogen; c) a hydrogen storage subsystem which stores purified and compressed hydrogen from said a hydrogen purification/compression subsystem in metal hydride storage tanks; d) a hydrogen transportation subsystem which transports the stored hydrogen in metal hydride storage tanks; and e) an end-use subsystem which receives distributed hydrogen from said hydrogen distribution subsystem and consumes said hydrogen.